title: Gene expression and biochemical changes of carbohydrate metabolism in in vitro micro-propagated apple plantlets infected by 'Candidatus Phytoplasma mali'.
abstract: 'Candidatus Phytoplasma mali' (Ca. P. mali) is the disease agent causing apple proliferation (AP), which has detrimental effects on production in many apple growing areas of Central and Southern Europe. The present study investigated transcriptional and biochemical changes related to the sugar metabolism as well as expression of pathogenesis-related (PR) protein genes in in vitro micro-propagated AP-infected and healthy control plantlets with the aim of shedding light on host plant response to 'Ca. P. mali' infection. Expression changes between infected and control plantlets were detected by quantitative real-time PCR analysis. The most significant transcriptional changes were observed for genes coding for pathogenesis-related proteins and for heat shock protein 70, as well as for some genes related to the sugar metabolism, such as a sorbitol transporter (SOT5), hexokinase, sucrose-phosphate synthase or granule bound starch synthase. Furthermore, biochemical analyses revealed that infected plantlets were characterized by a significant accumulation of starch and sucrose, while hexoses, such as glucose and fructose, and sorbitol were present at lower concentrations. In summary, the present analysis provides an overview of a gene set that is involved in response to phytoplasma infection and, therefore, it may help for a better understanding of the molecular mechanisms involved in phytoplasma-host plant interaction in apple.
authors.affiliation: Laimburg Research Centre for Agriculture and Forestry, Laimburg 6 - Pfatten (Vadena), 39040 Auer (Ora), BZ, Italy. mgiorno@science.ru.nl
authors.forename: Filomena
authors.initials: F
authors.lastname: Giorno
authors.forename: Gea
authors.initials: G
authors.lastname: Guerriero
authors.forename: Matteo
authors.initials: M
authors.lastname: Biagetti
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Ciccotti
authors.forename: Sanja
authors.initials: S
authors.lastname: Baric
mesh_terms: D050260:Carbohydrate Metabolism / Q000235:genetics*; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006601:Hexoses / Q000235:genetics / Q000378:metabolism; D054884:Host-Pathogen Interactions / Q000235:genetics; D027845:Malus / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D045582:Phytoplasma; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013213:Starch / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics; D013395:Sucrose / Q000378:metabolism
chemical_list: D018840:HSP70 Heat-Shock Proteins; D006601:Hexoses; D010940:Plant Proteins; D013395:Sucrose; D013213:Starch
keywords: APP; Apple proliferation; Carbohydrate metabolism; Gene expression; Hsp70; Malus x domestica; PR; PS II; Stress response; apple proliferation phytoplasma; heat shock protein 70; pathogenesis related; photosystem II; qRT-PCR; quantitative reverse transcriptase real-time PCR